I plan to explore the ways in which different types of auditory information, including linguistic, biological, and artificial sounds, are processed in the brain. More specifically, I will measure normal adults' abilities to discriminate these stimuli based on both motion and brief temporal differences. It is possible that linguistics stimuli, for which fast temporal processing is crucial, may be more easily processed in terms of motion. By matching non-identifiable sounds in complexity, spectral change, and band-width to each of the types of stimuli mentioned above, it will also be possible to determine if differences in the ways in which these sounds are processed are best attributed to physical differences in the stimuli or to the goals of processing. If the different types of stimuli are processed differently, it is likely that such processing involves different cortical areas. By using ERP and MEG methods, it will be possible to determine the precise times at which the processing of these different stimulus types is differentiated into different cortical pathways. By using fMRI, it will possible to determine which cortical areas are involved in processing auditory stimuli are involved in processing auditory stimuli with specific physical features and for specific goals.